We take memory for granted, like the air we breathe. Everything we do, see and think is shaped by habits and memories. My ability to write this book, and yours to read it, presupposes the memory of words and their meanings. My ability to ride a bicycle depends on unconscious habit memory. I can recall facts I have learned, like the year of the Battle of Hastings—1066; I can recognize people I first met years ago; I can remember specific incidents that happened when I was on holiday in Canada last summer. These are different kinds of memory, but all involve influences from the past that affect me in the present. Our memories underlie all our experience. And obviously animals have memories too.
How does memory work? Most people take it for granted that memories must somehow be stored in brains as material traces. In ancient Greece these traces were usually compared to impressions in wax. In the early twentieth century they were compared to connections between wires in a telephone exchange, and now they are thought of by analogy with memory-storage systems in computers. Although the metaphors change, the trace theory is taken for granted by most scientists, and almost everyone else.
From a materialist point of view, memories must be stored as material traces in brains. Where else could they be? The neuroscientist Steven Rose expressed the standard assumptions as follows:
Memories are in some way “in” the mind, and therefore, for a biologist, also “in” the brain. But how? The term memory must include at least two separate processes. It must involve, on the one hand, that of learning something new about the world around us; and on the other, at some later date, recalling, or remembering that thing. We infer that what lies between the learning and the remembering must be some permanent record, a memory trace, within the brain.1
This seems obvious and straightforward. It might seem pointless to question it. Yet the trace theory of memory is very questionable indeed. It raises appalling logical problems. Attempts to locate memory traces have been unsuccessful despite more than a century of research, costing many billions of dollars. For promissory materialists, this failure does not imply that the trace theory of memory might be wrong; it merely means that we need to spend more time and money searching for the elusive memory traces.
But memory traces are not the only option. Several philosophers in the ancient world, notably Plotinus, were skeptical that memories were material impressions, and argued that they were immaterial rather than material, aspects of the soul rather than the body.2 Likewise, more recent philosophers, like Henri Bergson, Alfred North Whitehead, Bertrand Russell and Ludwig Wittgenstein,3 saw memories as direct connections across time, not material structures in brains (see Chapter 4).
My own suggestion is that memories depend on morphic resonance. All individuals are influenced by morphic resonance from their own past. Morphic resonance depends on similarity; since organisms are more similar to themselves in the past than to other members of their species, self-resonance is highly specific. Individual memory and collective memory both depend on morphic resonance; they differ from each other in degree, not in kind.
I start with the trace theory of memory, then discuss the resonance hypothesis, and finally ways in which this hypothesis can be tested.
Several modern philosophers have pointed out that the trace theory of memory runs into an insoluble logical problem, quite apart from repeated failures to find memory traces.
In order for a memory trace to be consulted or reactivated, there has to be a retrieval system, and this system needs to identify the stored memory it is looking for. To do so it must recognize it, which means the retrieval system must itself have a memory. There is therefore a vicious regress: if the retrieval system is endowed with a memory store, this in turn requires a retrieval system with memory, and so on ad infinitum.4
There is a structural problem too. Memories can persist for decades, yet the nervous system is dynamic, continually changing, and so are the molecules within it. As Francis Crick put it, “Almost all the molecules in our bodies, with the exception of DNA, the genetic material, turn over in a matter of days, weeks, or at the most a few months. How then is memory stored in the brain so that its trace is relatively immune to molecular turnover?” He suggested a complex mechanism whereby molecules were replaced one at a time so as to preserve the overall state of the memory-storage structures.5 No such mechanism has been detected.
For decades, the most popular theory has been that memory must depend on changes in connections between nerve cells, the synapses. Yet attempts to locate memory stores have proved unsuccessful over and over again.
In the 1890s, Ivan Pavlov studied the way that animals such as dogs could learn to associate a stimulus, such as hearing a bell, with being fed. After repeated training, merely hearing the bell could cause the dogs to salivate. Pavlov called this a conditioned reflex. For many scientists at the time, this research suggested that the animals’ memory depended on reflex arcs, in which the nerve fibers were like wires and the brain like a telephone exchange. But Pavlov himself was reluctant to claim there were specific localized traces. He discovered that conditioning could survive massive surgical damage to the brain.6 Those who knew less about it were less cautious, and in the first few decades of the twentieth century many biologists assumed that all psychological activity, including the phenomena of the human mind, could ultimately be reduced to chains of reflexes wired together in the brain.
In a heroic series of experiments lasting more than thirty years, Karl Lashley (1890–1958) tried to locate specific memory traces, or “engrams,” in the brains of rats, monkeys and chimpanzees. He trained the animals in a variety of tasks ranging from simple conditioned reflexes to the solution of difficult problems. After the training, he surgically cut nerve tracts or removed portions of the brain and measured the effects on the animals’ memory. To his astonishment, he found that the animals could still remember what they had learned even after large amounts of brain tissue had been removed.
Lashley first became skeptical of the supposed path of conditioned reflex arcs through the motor cortex when he found that rats trained to respond in specific ways to light could perform almost as well as control rats after almost all their motor cortex was cut out. In similar experiments with monkeys, he removed most of the motor cortex after they had been trained to open boxes with latches. This operation resulted in a temporary paralysis. After two or three months, when they recovered their ability to move in a coordinated way, they were exposed to the puzzle boxes again. They opened them promptly without random exploratory movements.
Lashley then showed that learned habits were retained after the associative areas of the brain were destroyed. Habits also survived a series of deep incisions into the cerebral cortex that destroyed cross-connections within it. Moreover, if the cerebral cortex was intact, removal of subcortical structures such as the cerebellum did not destroy the memory either.
Lashley started as an enthusiastic supporter of the reflex theory of learning, but was forced to abandon it:
The original programme of research looked toward the tracing of conditioned-reflex arcs throughout the cortex … The experimental findings have never fitted into such a scheme. Rather, they have emphasised the unitary character of every habit, the impossibility of stating any learning as concatenations of reflexes, and the participation of large masses of nervous tissue in the functions rather than the development of restricted conduction paths.7
Lashley suggested that
the characteristics of the nervous network are such that when it is subject to any pattern of excitation, it may develop a pattern of activity, reduplicated through an entire functional area by spread of excitations, such as the surface of a liquid develops an interference pattern of spreading waves when it is disturbed at several points.
He suggested that recall involved “some sort of resonance among a very large number of neurons.”8 These ideas were carried further by his former student Karl Pribram in his proposal that memories are stored in a distributed manner throughout the brain analogous to the interference patterns in a hologram.9
Even in invertebrates specific memory traces have proved elusive. In a series of experiments with trained octopuses, learned habits survived when various parts of the brain were removed, leading to the seemingly paradoxical conclusion that “memory is both everywhere and nowhere in particular.”10
Despite these results, new generations of researchers have tried again and again to find localized memories. In the 1980s, Steven Rose and his colleagues thought they had at last succeeded in finding traces in the brains of day-old chicks. They trained the chicks to avoid pecking at little colored lights by making them sick, and the chicks duly avoided these stimuli when they encountered them again. Rose and his colleagues then studied the changes in the brains of these chicks, and found that nerve cells in a particular region of the left forebrain underwent more active growth and development when learning took place than when it did not.11
These findings agreed with results from studies of the growing brains of young rats, kittens and monkeys, which found that active nerve cells in the brain developed more than inactive nerve cells. But the greater development of active cells did not prove that they contained specific memory traces. When the region of active cells was surgically removed from the chicks’ left forebrains a day after training, the chicks could still remember what they had learned. Therefore the region of the brain involved in the learning process was not necessary for the retention of memory. Once again, the hypothetical memory traces proved elusive, and once more those who searched for them were forced to postulate unidentified “storage systems” somewhere else in the brain.12
In a more recent series of studies, mice were studied as they learned to negotiate a maze. The formation of memories involved activity in the median temporal lobes of the brain, particularly in the hippocampus. The ability to form long-term memories depended on a process called long-term potentiation, which involved protein synthesis in hippocampal nerve cells. But yet again, the memories proved elusive. Once the memories had been established, the destruction of the hippocampus on both sides of the brain failed to wipe them out. Thus, the researchers concluded, the hypothetical memory traces must somehow have moved from one part of the brain to another.
Erik Kandel, who won the Nobel Prize in 2000 for his work on memory in the sea slug, Aplysia, drew attention to some of these problems in his acceptance speech:
How do different regions of the hippocampus and the median temporal lobe … interact in the storage of explicit memory? We do not, for example, understand why the initial storage of memory requires the hippocampus, whereas the hippocampus is not required once a memory has been stored for weeks or months. What critical information does the hippocampus convey to the neo-cortex? We also know very little about the recall of explicit (declarative) memory … These systems properties of the brain will require more than the bottom-up approach of molecular biology.13
Currently, in the Connectome Project researchers at the Massachusetts Institute of Technology and elsewhere are trying to map some of the trillions of connections between nerve cells in mammalian brains, using thin slices of brain tissue and sophisticated computer analyses of the images. There are about 100 billion neurons in the human brain. As Sebastian Seung, the leader of the MIT team, pointed out, “In the cerebral cortex, it’s believed that one neuron is connected to 10,000 others.” This is a vastly ambitious project, but it seems unlikely to shed light on memory storage. First of all, a person has to be dead before his brain can be cut up, so changes before and after learning cannot be studied in this way. Second, there are great differences between the brains of different people; we do not have identical “wiring.”
The same is true of small animals like mice. A pilot project in the Max Planck Institute in Germany looked at the wiring diagrams for just fifteen neurons that control two small muscles in mouse ears. Even though this work was a technical tour de force, it revealed no unique wiring diagram. Even for the right and left ears of the same animal the patterns of connection were different.14
The most striking deviations from normal brain structure occur in people who suffered from hydrocephalus when they were babies. In this condition, also called “water on the brain,” much of the skull is filled with cerebrospinal fluid. The British neurologist John Lorber found that some people with extreme hydrocephalus were surprisingly normal, which led him to ask the provocative question: “Is the brain really necessary?” He scanned the brains of more than six hundred people with hydrocephalus, and found that about sixty had more than 95 percent of the cranial cavity filled with cerebrospinal fluid. Some were seriously retarded, but others were more or less normal, and some had IQs of well over 100. One young man who had an IQ of 126 and a first-class degree in mathematics, a student from Sheffield University, had “virtually no brain.” His skull was lined with a thin layer of brain cells about a millimeter thick, and the rest of the space was filled with fluid.15 Any attempt to explain his brain in terms of a standard “connectome” would be doomed to failure. His mental activity and his memory were still able to function more or less normally even though he had a brain only 5 percent of the normal size.
The available evidence shows that memories cannot be explained in terms of localized changes in synapses. Brain activity involves rhythmic patterns of electrical activity extended over thousands or millions of nerve cells, rather than simple reflex arcs like wires in a telephone exchange or wiring diagrams of computers. These patterns of nervous activity set up—and respond to—changes in the electromagnetic fields in the brain.16 The oscillating fields of entire brains are routinely measured in hospitals with electroencephalographs (EEG), and within these overall rhythms there are many subsidiary patterns of electrical activity in different regions of the brain. If these patterns, or systems properties, are to be remembered, resonance across time seems more likely than chemical storage in nerve endings.
More than a century of intensive, well-funded research has failed to pin down memory traces in brains. There may be a very simple reason for this: the hypothetical traces do not exist. However long or hard researchers look for them, they may never find them. Instead, memories may depend on morphic resonance from an organism’s own past. The brain may be more like a television set than a hard-drive recorder. What you see on TV depends on the resonant tuning of the set to invisible fields. No one can find out today what programs you watched yesterday by analyzing the wires and transistors in your TV set for traces of yesterday’s programs.
For the same reason, the fact that injury and brain degeneration, as in Alzheimer’s disease, lead to loss of memory does not prove that memories are stored in the damaged tissue. If I snipped a wire or removed some components from the sound circuits of your TV set, I could render it speechless, or aphasic. But this would not mean that all the sounds were stored in the damaged components.
Insects that undergo complete metamorphosis experience enormous changes in anatomy and lifestyle. It is hard to believe that a caterpillar chewing a leaf is the same organism as the moth that later emerges from the pupa. In the pupa, almost all the caterpillar tissues are dissolved before the new structures of the adult develop. Most of the nervous system is dissolved as well.
In a recent study, Martha Weiss and her colleagues at Georgetown University, Washington, found that moths could remember what they had learned as caterpillars in spite of all the changes they went through during metamorphosis. They trained caterpillars of the Carolina Sphinx moth, Manduca sexta, to avoid the odor of ethyl acetate by associating exposure to this odor with a mild electric shock. After two larval molts and metamorphosis within the pupae, the adult moths were averse to ethyl acetate, despite that radical transformation of their nervous system. Weiss and her colleagues carried out careful controls that showed this was a real transfer of learning, not just a carryover of odors absorbed by the tested caterpillars.17
This ability of adult moths to remember their experience as caterpillars may well be of evolutionary significance. If the plants that moths have experienced as caterpillars influence the behavior of adults, the female moths will tend to avoid laying eggs on harmful plants and favor nutritious ones, even if members of the species have never encountered these plants before. New patterns of preference for particular host plants could be established in a single generation, and would persist in their offspring; a species could evolve new feeding habits very rapidly.
The carryover of learning from caterpillar to moth after the dissolution of most of the nervous system would be very puzzling indeed if all memories were stored as material traces, but there is already evidence from higher animals and humans that memories may not be stored in traces and can survive substantial damage to brains.
Brain damage can result in two kinds of memory loss: retrograde (backward) amnesia, forgetting what happened before the damage, and anterograde (forward) amnesia, losing the ability to remember what happens after the damage.
The best-known examples of retrograde amnesia occur after concussion. As a result of a sudden blow on the head a person loses consciousness and becomes paralyzed for a few seconds or for many days, depending on the severity of the impact. As she recovers and regains the ability to speak, she may seem normal in most respects, but is unable to recall what happened before the accident. Typically, as recovery proceeds, the first of the forgotten events to be recalled are those longest ago; the memory of more recent events returns progressively.
In such cases, amnesia cannot be due to the destruction of memory traces, for the lost memories return. Karl Lashley reached a similar conclusion years ago:
I believe that the evidence strongly favours the view that amnesia from brain injury rarely, if ever, is due to the destruction of specific memory traces. Rather, the amnesias represent a lowered level of vigilance, a greater difficulty in activating the organized pattern of traces, or a disturbance of some broader system of organized functions.18
Although many memories return, the events immediately preceding a blow on the head may never be recovered: there may be a permanent blank period. For example, a motorist may remember approaching the crossroads where an accident occurred, but nothing more. A similar “momentary retrograde amnesia” also occurs as a result of electroconvulsive therapy, administered to some psychiatric patients by passing a burst of electric current through their heads. They usually cannot remember what happened immediately before the administration of the shock.19
Events and information in short-term memory are forgotten because a loss of consciousness prevents them being connected up into patterns of relationship that can be remembered. The failure to make such connections, and hence to turn short-term memories into long-term memories, often persists for some time after a concussed patient has regained consciousness, and is sometimes described as “memorizing defect.” People in this condition rapidly forget events almost as soon as they occur.
Everyone agrees that the formation of memories is an active process. Either the inability to construct them prevents new memory traces being formed; or this inability prevents the formation of new morphic fields, resonant patterns of activity, and if these patterns are not formed in the first place, they cannot be recalled by morphic resonance.
Some kinds of brain damage have very specific effects on people’s abilities to recognize and recall,20 and others cause specific disorders, such as aphasias (disorders of language use) resulting from lesions in various parts of the cortex in the left hemisphere. These kinds of damage disturb the organized patterns of activity in the brain,21 and affect the brain’s ability to tune in to skills and memories by morphic resonance.
In a famous series of investigations carried out during brain surgery on conscious patients, Wilder Penfield and his colleagues tested the effects of mild electrical stimulation of various regions of the cerebral cortex. As the electrode touched parts of the motor cortex, limbs moved. Electrically stimulating the auditory or visual cortex evoked auditory or visual hallucinations like buzzing noises or flashes of light. Stimulation of the secondary visual cortex gave hallucinations of flowers, for example, or animals, or familiar people. When some regions of the temporal cortex were stimulated, some patients recalled dream-like memories, for example of a concert or a telephone conversation.22
Penfield initially assumed that the electrical evocation of memories meant that they were stored in the stimulated tissue, which he named the “memory cortex.” On further consideration, he changed his mind: “This was a mistake … The record is not in the cortex.”23 Like Lashley and Pribram, he gave up the idea of localized memory traces in favor of the theory that they were widely distributed in other parts of the brain.
The most popular analogy for distributed memory storage is holography, a form of lens-less photography in which interference patterns are stored as holograms, from which the original image can be reconstructed in three dimensions. If part of the hologram is destroyed, the whole image can still be reconstructed from the remaining parts, although in lower definition. The whole is present in each part. This may sound mysterious, but the basic principle is simple and familiar. As you look around you now, your eyes are sampling light from all the parts of the scene in front of you. The light absorbed by your eyes is only a small part of the available light, and yet you can see the whole scene. If you move a few feet, you can still see everything, the whole scene is present there too, although you are now sampling the light waves in a different place. In a similar way, the whole is enfolded into each part of a hologram. This is not true of an ordinary photograph: if you tear off half the photo, you have lost half the image. If you tear off half a hologram, the whole image can still be re-created.
But what if the holographic wave patterns are not stored in the brain at all? Pribram later came to this conclusion, and thought of the brain as a “waveform analyzer” rather than a storage system, comparing it to a radio receiver that picked up waveforms from the “implicate order,” rendering them explicate.24 This aspect of his thinking was influenced by the quantum physicist David Bohm, who suggested that the entire universe is holographic, in the sense that wholeness is enfolded into every part.25
According to Bohm, the observable or manifest world is the explicate or unfolded order, which emerges from the implicate or enfolded order.26 Bohm thought that the implicate order contains a kind of memory. What happens in one place is “introjected” or “injected” into the implicate order, which is potentially present everywhere; thereafter when the implicate order unfolds into the explicate order, this memory affects what happens, giving the process very similar properties to morphic resonance. In Bohm’s words, each moment will “contain a projection of the re-injection of the previous moments, which is a kind of memory; so that would result in a general replication of past forms.”27
Maybe morphic resonance will one day be included in an enlarged version of quantum theory, as Bohm suggested. No one yet knows. The question “How can morphic resonance be explained?” is open. In the context of a debate about the reality of memory traces, does morphic resonance—or memory in the implicate order—fit the facts better than the trace theory?
The trace theory says that memories are stored materially in brains, for example as chemicals in synapses. The alternative is the resonance theory: memories are transferred by resonance from similar patterns of activity in the past. We tune in to ourselves in the past; we do not carry our memories around inside our heads.
The resonance of memory is part of a much wider hypothesis. The hypothesis of morphic resonance proposes a resonance across space and time of patterns of vibratory activity in all self-organizing systems.28 Morphic resonance underlies habits of crystallization and protein folding (see Chapter 3). It also underlies the inheritance of morphogenetic fields and of patterns of instinctive behavior (see Chapter 6). It plays an essential role in the transfer of learning, as discussed below. Morphic resonance provides a new way of looking at memories. There are at least five kinds of memory: habituation, sensitization, behavioral memory, recognition and recalling.
Habituation means getting used to things. If you hear a new sound, or smell a new smell, you may pay attention to it to start with, but if it makes no difference, you soon cease to notice it. You don’t notice the pressure of your clothes on your body most of the time, or the pressure of your bottom on the seat on which you are sitting, or the sounds of a clock ticking, or the many other background noises around you.
Habituation is one of the most fundamental kinds of memory and underlies all our responses to our environment. Generally speaking, we do not notice what stays the same; we notice changes or differences. All our senses work on this principle. If you are gazing over a landscape, anything that moves immediately catches your eye. If there is a change in the background noise, you notice it. Our entire culture works on the same principle, which is why gossip and newspapers rarely concern themselves with things that stay the same. They are about changes or differences.
Other animals likewise become accustomed to their environments. They generally react to something new because they are not used to it, often showing alarm or avoidance. This kind of response even occurs in single-celled animals like Stentor raesilii, which lives in marshy pools. Each Stentor is a trumpet-shaped cell covered with rows of fine, beating hairs called cilia. The activity of the cilia sets up currents around the cell, carrying suspended particles to the mouth, which is at the bottom of a tiny vortex (Figure 7.1). These cells are attached at their base by a “foot,” and the lower part of the cell is surrounded by a mucus-like tube. If the surface to which it is attached is slightly jolted, Stentor rapidly contracts into its tube. If nothing happens, after about half a minute it extends again and the cilia resume their activity. If the same stimulus is repeated, it does not contract but continues its normal activities. This is not a result of fatigue because the cell responds to a new stimulus, such as being touched, by contracting again.29
FIGURE 7.1A: The single-celled organism Stentor raesilii, showing the currents of water around it caused by the beating of its cilia. In response to an unfamiliar stimulus it rapidly contracts into its tube (B). (After Jennings, 1906)
The cell membranes of Stentor have an electrical charge across them, just like nerve cells. When they are stimulated, an action potential sweeps over the surface of the cell, very similar to a nerve impulse, and this leads to the cell contracting.30 As it becomes habituated, the receptors on the cell’s membrane become less sensitive to mechanical stimulation, and the action potential is not triggered.31 Since Stentor is a single cell, its memory cannot be explained in terms of changes in nerve endings, or synapses, because it has none.
Habituation implies a kind of memory that enables harmless and irrelevant stimuli to be recognized when they recur. Morphic resonance suggests a straightforward explanation. The organism is in resonance with its own past patterns of activity, including its return to normal following its withdrawal response to a harmless stimulus. When the stimulus is repeated, the organism resonates with its previous pattern of response, including the return to normal activity. It returns to normal activity sooner, and responds less and less, until the harmless stimuli are ignored. It habituates through self-resonance. A new stimulus stands out precisely because it is new and unfamiliar.
Habituation occurs in all animals, large and small, with and without nervous systems. The effects of habituation have been studied in detail in the giant marine slug Aplysia, which grows more than a foot long. Its nervous system is relatively simple, and is similar in different individuals. Normally the slug’s gill is extended, but if the slug is touched, the gill is withdrawn. This reflex soon ceases if harmless stimuli are repeated; the slugs habituate, just like Stentor. Eric Kandel and his group showed that only four motor nerve cells are responsible for the gill withdrawal response. As habituation occurs, the sensory nerve cells cease to excite the motor cells because they release fewer and fewer packets of chemical transmitter at the synapses with the motor cells. But the fact that the synapses function differently as a result of habituation does not prove that the memory is stored chemically in the synapses. The entire system may habituate as a result of self-resonance, as in Stentor. Self-resonance may underlie habituation in animals at all levels of complexity, including ourselves.
Sensitization is the opposite of habituation: animals become more responsive to stimuli that have a harmful effect. Again, even single-celled animals like Stentor exhibit this kind of behavior. If a stream of noxious particles is directed at Stentor, it contracts into its tube. The next time it is exposed to the same particles it contracts more rapidly, and after several exposures, it goes on contracting inside its tube until its foot is detached; it swims away until it finds a more peaceful place to settle down, where it builds a new tube and resumes its normal life. Aplysia shows a similar kind of sensitization, and Kandel and his group have described several changes that occur in the nerve cells as this happens. Whereas habituation results in less neurotransmitter being released by sensory neurons in their synapses with motor neurons, sensitization results in more being released.32
Again, there is no need to suppose that the memory that underlies sensitization is stored in the form of chemical changes inside the cells. Like habituation, sensitization fits well with a self-resonance model. When a stimulus that proved harmful in the past occurs, the organism resonates with itself, responding to the same stimulus, resulting in a greater response. In addition, sensitization can reach a threshold where the organism does something different. Stentor swims away.33 Aplysia releases toxic ink containing hydrogen peroxide.34
Many animals learn patterns of behavior from other members of their group through imitation. For example, some species of bird, like blackbirds, learn parts of songs by listening to the songs of nearby adults. This is a kind of cultural inheritance.
Cultural inheritance reaches its highest development in humanity where all human beings learn a great variety of patterns of behavior, including the use of language, as well as many physical and mental skills, like doing arithmetic, playing the flute or knitting. From the point of view of morphic resonance, the transfer of these skills is a kind of resonance process.
In the 1980s, neuroscientists discovered that when animals watched other animals carrying out a particular action, changes in the motor part of their brains mirrored those in the brains of the animals they were watching. These responses are often described in terms of “mirror neurons”: the brain activity mirrors that of the animal being watched, and involves the same sorts of changes that take place in carrying out the action itself. But the term mirror neuron is misleading if it suggests that special kinds of nerves are required for this activity. Instead, it is better thought of as a kind of resonance. In fact, Vittorio Gallese, one of the discoverers of mirror neurons, refers to the imitation of movements or actions by another individual as “resonance behavior.”35
Resonance behavior is a new phrase, but the phenomenon itself is not a new discovery. The entire pornography industry depends on it. Watching other people engaged in sexual activity stimulates erotic arousal by a kind of resonance.
Some neuroscientists have extended the idea of mirror systems to what they call a “motor resonance theory of mind reading,” whereby the nervous system responds “to execution and observation of goal-oriented actions.”36 This resonance is not confined to the brain but to the entire pattern of movements of the body as well, and no doubt plays a major part in the learning of skills, such as riding a bicycle, and in other forms of “learning by doing.”
Through repetition, behavioral patterns and skills improve, and become increasingly habitual. Both the acquisition of new patterns of behavior and remembering them fit well with a resonance model.
Recognition involves the awareness that a present experience is also remembered: we know that we were in this place before, or met this person somewhere, or came across this fact or idea. But we may not be able to recall where or when, or recall the person’s or the place’s name. Recognition and recall are different kinds of memory: recognition depends on a similarity between present experience and previous experience. Recall involves an active reconstruction of the past on the basis of remembered meanings or connections.
Recognizing is easier than recalling. For example, it is usually easier to recognize people than remember their names. Most of us have remarkable powers of recognition that we usually take for granted. Many laboratory experiments have demonstrated just how powerful this ability can be. For example, in one study, subjects were asked to memorize a meaningless shape. When they were asked to recall it by drawing it, their ability to do so declined rapidly within minutes. By contrast, most people could pick out the test shape from a range of similar shapes weeks later.37
Recognition, like habituation, depends on morphic resonance with previous similar patterns of activity. The pattern of vibratory activity within your sensory organs and nervous system when you see a person you know is similar to the pattern when you saw the same person before. The sensory stimuli are similar and have similar effects on the sense organs and the nervous system. The greater the similarity, the stronger the resonance.
Conscious recall is an active process. The ability to recall a particular experience depends on the ways we made connections in the first place. To the extent that we use language to categorize and connect the elements of experience, we can use language to help reconstruct these past patterns. But we cannot recall connections that were not made to start with.
Our short-term memory for words and phrases enables us to remember them long enough to grasp their connections and understand their meanings. We usually remember meanings—patterns of connection—rather than the actual words. It is relatively easy to summarize the gist of a recent conversation but, for most of us, impossible to reproduce it verbatim. The same is true of written language: you may recall some of the facts and ideas in the preceding chapters of this book, but you will probably recall very few passages word for word.
Short-term memories provide the opportunities for elements of our near-present experience to be connected with each other, as well as with past experience. What is not connected is forgotten. Short-term memory is often compared to a computer’s RAM (Random Access Memory), and has a very limited capacity, typically 7±2 items. In the 1940s, the neuroscientist Donald Hebb pointed out that such short-term memories, lasting less than a minute, were unlikely to be stored chemically and suggested that they might depend on reverberating circuits of electrical activity—again implying a process of resonance.
In the case of spatial recall—for instance, in remembering the layout of a particular house—the connections between different spaces are related to movements of the body; for example, along a corridor, climbing stairs and entering a room.
The principles of memorizing and recalling have long been understood; the basic principles of mnemonic systems were well known in classical times and were taught to students of rhetoric, providing techniques for establishing connections that enable items to be recalled more easily.38 Some methods depend on verbal connections and involve coding the information in rhymes, phrases or sentences. For instance, “Richard Of York Gained Battles In Vain” is a well-known mnemonic for the colors of the rainbow (Red, Orange, Yellow, Green, Blue, Indigo, Violet). Other systems are spatial and rely on visual imagery. For instance, in the “method of loci” one first memorizes a sequence of locations; for example, the various rooms and cupboards of one’s own house. Each item to be recalled is then visualized in one of these locations, and remembered by imagining walking from one place to the other and finding the object there. Modern mnemonic systems, such as systems for improving your memory power advertized in popular magazines, are the heirs of this long and rich tradition.39
Memorizing spatial patterns in many animals depends on the activity of the hippocampus, as discussed above, and the activity of the brain in this and other regions seems to be necessary for connecting together the items to be recalled. Between being laid down and recalled, the memories are usually supposed to be encoded in elusive long-term memory traces. The resonance hypothesis fits the facts better. The pattern of connections established when the memories are formed is associated with rhythmic patterns of brain activity. The memories are recalled through similar patterns of activity established by morphic resonance. They are not stored as traces in the brain.
If memories are stored in individual animals’ brains, then anything an animal learns is confined to its own brain. When it dies the memory is extinguished. But if memory is a resonant phenomenon through which organisms specifically resonate with themselves in the past, individual memory and collective memory are different aspects of the same phenomenon; they differ in degree, not in kind.
This hypothesis is testable. If rats learn a new trick in one place, then rats all over the world should be able to learn the same trick quicker. The more rats that learn it, the easier it should become everywhere else. There is already evidence from one of the longest series of experiments in the history of psychology that rats do indeed seem to learn quicker what other rats have already learned. The more that learned to escape from a water maze, the easier it became for others to do so. These experiments, conducted first at Harvard, then at Edinburgh and Melbourne universities, showed that the Scottish and Australian rats took up more or less where the Harvard rats had left off, and their descendants learned even faster. Some got it right first time with no need for learning at all. In the experiment at Melbourne University, a line of control rats, whose parents had never been trained, showed the same pattern of improvement as rats descended from trained parents, showing that this effect was not passed through the genes, or through epigenetic modifications of genes. All similar rats learned quicker, just as the hypothesis of morphic resonance would predict.40
Likewise, humans should be able to learn more easily what others have already learned. New skills like snowboarding and playing computer games should become easier to learn, on average. Of course there will always be faster and slower learners, but the general tendency should be toward quicker learning. Much anecdotal evidence suggests that this is so. But for hard, quantitative evidence, the best place to look is in standardized tests that have remained more or less the same over decades. Intelligence quotient (IQ) tests are a good example. By morphic resonance, the questions should become easier to answer because so many people have answered them before. The scores in the tests should rise not because people are becoming more intelligent but because the tests are becoming easier to do. Just such an effect has in fact occurred and is known as the Flynn effect after the psychologist James Flynn, who has done so much to document this phenomenon.41 Average IQ test scores have been rising for decades by 30 percent or more. Data from the United States are in Figure 7.2.
FIGURE 7.2. THE FLYNN EFFECT: changes in average IQ scores in the United States, relative to 1989 values.42
There has been a long debate among psychologists about possible reasons for the Flynn effect. Attempted explanations in terms of nutrition, urbanization, exposure to TV and practice with examinations seem to account for only a small part of this effect. At first Flynn confessed himself baffled, and has tried out a number of ever more complex explanations. His most recent attempt ascribes this effect to a change in the general culture:
The best short-hand description I can offer is this. During the twentieth century, people invested their intelligence in the solution of new cognitive problems. Formal education played a proximate causal role but a full appreciation of causes involves grasping the total impact of the industrial revolution.43
The trouble is that this hypothesis is vague, obscure and untestable. Morphic resonance provides a simpler explanation.
Scientists in universities in Europe and America have already carried out a series of tests specifically designed to test for morphic resonance in human learning, particularly in connection with written languages. Most have given positive, statistically significant results.44 This is inevitably a controversial area of research but, unlike Flynn’s hypothesis, morphic resonance is relatively easy to test with animals and people.
I find it makes a big difference to think of tuning in to my memories, instead of retrieving them from stores inside my brain by obscure molecular mechanisms. Resonance feels more plausible and fits better with experience. It is also more compatible with the findings of brain research: memory traces are nowhere to be found.
In research there would be a shift of focus from the molecular details of nerve cells to the transfer of memory by resonance. This shift would also open up the question of collective memory, which the psychologist C. G. Jung thought of in terms of the collective unconscious.
If learning involves a process of resonance not only with the teacher who is transmitting the skill, but all those who have learned it before, educational methods could be improved by deliberately enhancing the process of resonance, leading to a faster and more effective transfer of skills.
The resonance theory of memory also opens up a religious question. All religions take it for granted that some aspect of a person’s memory survives that person’s bodily death. In Hindu and Buddhist theories of reincarnation or rebirth, memories, habits or tendencies are carried over from one life to another. This transfer of memory is part of the action of karma, a kind of causation across time; actions bring about effects in the future, even in later lives. In Christianity there are several different theories of survival, but all imply a survival of memory. According to the Roman Catholic doctrine of Purgatory, after death believers enter an ongoing process of development, comparable to dreaming. This process would make no sense unless the person’s memories played a part in the process. Some Protestants believe that after death everyone goes to sleep, only to be resurrected just before the Last Judgment. But this theory too requires a survival of memory because the Last Judgment would be meaningless if the person being judged had forgotten who he was and what he had done.
By contrast, the materialist theory is simple. Memories are in the brain; the brain decays at death; therefore all memories are wiped out forever. For an atheist, what could be a better proof of the folly of religious belief? All religious theories of survival are impossible because they all rely on the survival of personal memories, which are wiped out when the brain decays. The materialist theory leaves the question of the survival of bodily death closed. By contrast, the resonance theory leaves the question open. Memories themselves do not decay at death, but can continue to act by resonance, as long as there is a vibratory system that they can resonate with. They contribute to the collective memory of the species. But whether or not there is an immaterial part of the self that can still access these memories in the absence of a brain is another question.
Do you believe that memories are stored as material traces in brains? If so, can you summarize the evidence?
How do you think memory-retrieval systems recognize the memories they are trying to retrieve from memory stores?
Have you ever considered the possibility that memory might depend on some kind of resonance rather than on material traces?
If the trace theory of memory is a testable hypothesis, rather than a dogma, how could it be established experimentally that memory depends on traces rather than resonance?
SUMMARY
Repeated failures to find memory traces fit well with the idea of memory as a resonant phenomenon, where similar patterns of activity in the past affect present activities in minds and brains. Individual and collective memory both depend on resonance, but self-resonance from an individual’s own past is more specific and hence more effective. Animal and human learning may be transmitted by morphic resonance across space and time. The resonance theory helps account for the ability of memories to survive serious damage to brains, and is consistent with all known kinds of remembering. This theory predicts that if animals, say, rats, learn a new trick in one place, say, Harvard, rats all over the world should be able to learn it faster thereafter. There is already evidence that this actually happens. Similar principles apply to human learning. For example, if millions of people take standard tests, like IQ tests, the tests should become progressively easier, on average, for other people to do. Again, this seems to be what happens. Individual memory and collective memory are different aspects of the same phenomenon and differ in degree, not in kind.